The patent strain CGMCC No. 4316 of Absidia glauca is capable of converting ginsenoside Rb1into Rd specifically. The research was conducted to optimize the factors of fermentation broth and related conditions by TCL assay based on single factor test associated with response surface methodology,and the activity of ginsenoside-glycosidase was used as response value to establish regression model. The results showed that under the optimal conditions of wheat bran 20. 47 g /L as carbon source,peptone 9. 74 g /L as nitrogen source,initial pH 6. 0,culture medium volume 45 mL /250 mL,shake flask revolutions of 180 r /min,inventory 10. 00%,culture temperature 30 ℃ for 72 h fermentation,the enzyme activity reached 92. 78 U /mL.